Process for secondary oil recovery



2,838,118 Patented June 10, 1958 PROCESS FOR SECONDARY OIL RECOVERY: DYNAMIC CYCLE SYSTEM Simon L. Ruskin, New York, N. Y., and Charles W. Ripple, Union County, N. J.

No Drawing. Application March 3, 1955 Serial No. 492,050

2 Claims. Cl. 166-42) This invention relates to secondary oil recovery and methods to promote recovery of oilsand gases locked in sedimentary rocks.

We have found that hydrocarbons are held in sand and clay particularly of marine sedimentary structures by long range molecular forces such as exist between the lattice structure of silicates and carbonates, and that aggregates of silicate and carbonate crystals exert these forces on aggregates of hydrocarbon molecules so that there is dispersed throughout the oil-bearing rock these interstitial deposits. Similarly there is held aggregates of water molecules which are held by a combination of these longer range forces as Well as polar forces from the water molecule itself. These combined attractions are greater than the attractions exerted on the non-polar oil aggregates.

The oil industry has for many years resorted to the use of water flooding in order to displace the oil aggregates from the rock and so stimulate secondary oil recovery. This has in general been unsuccessful primarily due to the fact that the water flooded into the area followed its own channels through the rock without ap proaching the bound oil aggregates. Another reason for the failure is the nature. of the disposition of the connate water and the oil which exist in the rock in stable equilibrium. There is thus no reason for either a change in the connate water or in the bound oil aggregates in the flooded areas. The initial pressures of the water injected in the iicodin operation is rapidly spent in the friction due to the intercrystal channels which are microscopic in size.

We have found that this stable state could be converted into a dynamic state of flow by lowering the viscosity of the bound oil aggregates as well as that of the connate water and simultaneously supply a source of energy to satisfy the thermodynamic state that is established.

To practise our invention we dissolve acetylene gas in acetone to the saturation point of the acetone and this acetylene saturated acetone is added to the water to be used for flooding. Lower concentrations than saturation of acetylene may also be used as desired, depending on the oil bearing formation. The water acetone mixture may be saturated with acetylene gas under 10 to 15 atmospheres pressure and while held at this pressure used for flooding through the well into the oil-bearing rock.

The acetone acetylene water mixture is mixed in a ratio that will lower the viscosity of the oil. Acetylene gas will of itself lower the viscosity of oil and the amount of acetone added may be adjusted so as to keep a lower viscosity of the water used in this process as compared to free water.

The acetone acetylene mixture has a high adsorptive action on silicates and the heat of adsorption added to the heat adsorption of the low viscosity Water answers the thermodynamic requirements for the displacement of the connate water. At the same time difiusion of the acetylene under the gradually falling pressure dissolves in the bound hydrocarbons and lowers the viscosity of the oil thus creating a dynamic cycle of flow from the previously stable rock cells. Since these cells resemble in some respects physiological conditions, this dynamic state 5 is'cylic in nature with a continuous output of the oil and intake of the acetylene acetone water mixture. Experimental work has shown that crude oil ,at 140 F. has a viscosity of 225/ sec. Ostwald. After treating with acetylene at 140 F. the viscosity fell to l9 5/sec. Ostwald.

10 A graphic representation of this cycle is as follows:

acetone water mixture ecetylene 30 atmospheres acetylene silicate acetone wete:

d ti dissolves cit 6 Sup WK acetylene r place d acetylene in silk:

acetylene release 01 lower: viscosity reabsorbed by hydrocarbons of hydrocarbons eilicate K provides acetylene in-lolufiun paraifinic hydrocarbon removed acetylene :elei'aed from ,1 hydrocarbon as pressure 1- reduced While in the customary water flooding the water' follows the channels already water-bearing and thus by passes the oil channels, our water acetone acetylene mixture exerts a degree of'continuous gas liberation which enters oil channels as well as water channels. The acetylene acetone or the acetyleneitself. lowers theviscosity of the bound oil and connate water so that the mixture can enter; the cell. This condition is closely related to the physiological entrance of chemicals into, tissue cells.

The differential solubility of acetylene in water under various pressures makes it ideally suitable to inject into the formation. Since the acetylene is less soluble in the water at reduced pressure and more soluble in the oil at the reduced pressure, thus reducing the viscosity of the oil and aiding it to flow. V

Instead of a water acetone acetylene system, we may also employ just water and acetylene. While water and gas such as methane and propane have previously been employed, we have found that the methane propane gases do not possess the necessary solubility in water to create the dynamic state of equilibrium essential for the operation of our dynamic cycle. It has therefore lacked the efliciency of our procedure. saturated bond also plays a role in the relationship to hydrocarbon viscosity that is more favorable for our system. 7

Our dynamic cycle system may be applied either in the center of the field or supplemented by wells to which the dynamic cycle is applied in the four corners of the field. The acetylene can be generated at the field or be used in tanks ready mixed with acetone and Water. Instead of acetone one may employ other acetylene solvents or adsorbents.

Another method for the employment of our dynamic cyclesystem is to employ the acetylene adsorbed on sand such as kieselguhr, kaolin, calcite or silicate compositions, 7

The triple non- By the same process we may treat oil-bearing rock.

sands, shales, sediments or -other oil-bearing natural deposits. The sandfracturing procedure may be used preparatory to the application of acetylene gas or the flooding of the formation with acetylene water acetone mixture. Or the sandfracturing may even follow the preliminary injection of acetylene into the formation.

Instead of acetone, other organic solvents for acetylene similar to acetone may be used which will lower the viscosity of the hydrocarbons bound in the oil formations. Since the solubility. of acetylene in water is a one to one ratio, and the ratio of solubility of acetylene to acetone is 300 parts acetylene in one of acetone at 59 F. and 12 atmospheres pressure, the acetone acts as a reservoir containing acetylene as the water allows the escape of acetylene with falling temperature and pressure.

Instead of acetylene we may use acetylene mixed with other hydrocarbon gases.

Instead of acetone we may use other organic solvents in which acetylene and other hydrocarbon mixtures are appreciably soluble.

' Example One thousand barrels of water are filled into tanks where one part to 1000 parts of acetone are added. Acetylene gas is run into the tank under 500 to 1000 pounds pressure until saturation of the water acetone mixture is obtained. The mixture is now introduced into the well under 500 lbs. to 1000 lbs. pressure so that it spreads into the oil-bearing rock to start the dynamic cycle. When the oil flow begins, the further addition of acetylene mixture may be stopped. While this procedure is used I for secondary oil recovery, it may also be employed for starting fresh.

What we claim is: e

l. A process for releasing oil from an oil-bearing deposit, said process comprising providing a solution of acetylene under a pressure greater than atmospheric, introducing said solution into said deposit while maintaining a pressure greater than atmospheric, reducing said pressure to release at least a portion of said acetylene from said solution, and dissolve at least a portion of said released acetylene in said oil thereby reducing the viscosity of said oil and transporting said oil from said deposit.

2. A process for releasing oil from an oil-bearing deposit, said process comprising providing a solution of water, acetone and acetylene under a pressure greater than atmospheric, introducing said solution into said deposit while maintaining a pressure greater than at mospheric, reducing said pressure to release at least a portion of said acetylene from said solution, and dissolve at least a portion' of said released acetylene in said oil thereby reducing the viscosity of said oil and transporting said oil from said deposit.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Martin: Flooding With Carboned Water, The Oil and Gas Journal, August 1951, pages 70, 71, 86 and 87. 

1. A PROCESS FOR RELEASING OIL FROM AN OIL-BEARIN DEPOSIT, SAID PROCESS COMPRISING PROVIDING A SOLUTION OF ACETYLENE UNDER A PRESSURE GREATHER THAN ATMOSPHERIC, INTRODUCING SAID SOLUTION INTO SAID DEPOSIT WHILE MAINTAINING A PRESSURE GREATHER THAN ATMOSPHERIC, REDUCING SAID PRESSURE TO RELASE AT LEAST A PORTION OF SAID ACCEYLENE FROM SAID SOLUTION, AND DISSOLVE AT LEAST A PORTION OF SAID RELEASED ACETYLENE IN SAID OIL THEREBY REDUCING SAID VISOSITY OF SAID OIL AND TRANSPORTING SAID OIL FROM SAID DEPOSIT. 